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.. _4.1.10_py:
4.1.10 Smart Fan
=========================
Introduction
-----------------
In this project, we will use motors, buttons and thermistors to make a
manual + automatic smart fan whose wind speed is adjustable.
Required Components
------------------------------
In this project, we need the following components.
.. image:: ../img/list_Smart_Fan.png
:align: center
It's definitely convenient to buy a whole kit, here's the link:
.. list-table::
:widths: 20 20 20
:header-rows: 1
* - Name
- ITEMS IN THIS KIT
- LINK
* - Raphael Kit
- 337
- |link_Raphael_kit|
You can also buy them separately from the links below.
.. list-table::
:widths: 30 20
:header-rows: 1
* - COMPONENT INTRODUCTION
- PURCHASE LINK
* - :ref:`cpn_gpio_extension_board`
- |link_gpio_board_buy|
* - :ref:`cpn_breadboard`
- |link_breadboard_buy|
* - :ref:`cpn_wires`
- |link_wires_buy|
* - :ref:`cpn_resistor`
- |link_resistor_buy|
* - :ref:`cpn_power_module`
- \-
* - :ref:`cpn_thermistor`
- |link_thermistor_buy|
* - :ref:`cpn_l293d`
- \-
* - :ref:`cpn_adc0834`
- \-
* - :ref:`cpn_button`
- |link_button_buy|
* - :ref:`cpn_motor`
- |link_motor_buy|
Schematic Diagram
------------------------
============ ======== ======== ===
T-Board Name physical wiringPi BCM
GPIO17 Pin 11 0 17
GPIO18 Pin 12 1 18
GPIO27 Pin 13 2 27
GPIO22 Pin 15 3 22
GPIO5 Pin 29 21 5
GPIO6 Pin 31 22 6
GPIO13 Pin 33 23 13
============ ======== ======== ===
.. image:: ../img/Schematic_three_one4.png
:align: center
Experimental Procedures
-----------------------------
**Step 1:** Build the circuit.
.. image:: ../img/image245.png
.. note::
The power module can apply a 9V battery with the 9V Battery
Buckle in the kit. Insert the jumper cap of the power module into the 5V
bus strips of the breadboard.
.. image:: ../img/image118.jpeg
:align: center
**Step 2**: Get into the folder of the code.
.. raw:: html
.. code-block::
cd ~/raphael-kit/python
**Step 3**: Run.
.. raw:: html
.. code-block::
sudo python3 4.1.10_SmartFan.py
As the code runs, start the fan by pressing the button. Every time you
press, 1 speed grade is adjusted up or down. There are **5** kinds of
speed grades: **0~4**. When set to the 4\ :sup:`th` speed grade and you
press the button, the fan stops working with a **0** wind speed.
Once the temperature goes up or down for more than 2℃, the speed
automatically gets 1-grade faster or slower.
Code
--------
.. note::
You can **Modify/Reset/Copy/Run/Stop** the code below. But before that, you need to go to source code path like ``raphael-kit/python``. After modifying the code, you can run it directly to see the effect.
.. raw:: html
.. code-block:: python
import RPi.GPIO as GPIO
import time
import ADC0834
import math
# Set up pins
MotorPin1 = 5
MotorPin2 = 6
MotorEnable = 13
BtnPin = 22
def setup():
global p_M1,p_M2
ADC0834.setup()
GPIO.setmode(GPIO.BCM)
GPIO.setup(MotorPin1, GPIO.OUT)
GPIO.setup(MotorPin2, GPIO.OUT)
p_M1=GPIO.PWM(MotorPin1,2000)
p_M2=GPIO.PWM(MotorPin2,2000)
p_M1.start(0)
p_M2.start(0)
GPIO.setup(MotorEnable, GPIO.OUT, initial=GPIO.LOW)
GPIO.setup(BtnPin, GPIO.IN)
def temperature():
analogVal = ADC0834.getResult()
Vr = 5 * float(analogVal) / 255
Rt = 10000 * Vr / (5 - Vr)
temp = 1/(((math.log(Rt / 10000)) / 3950) + (1 / (273.15+25)))
Cel = temp - 273.15
Fah = Cel * 1.8 + 32
return Cel
def motor(level):
if level == 0:
GPIO.output(MotorEnable, GPIO.LOW)
return 0
if level>=4:
level = 4
GPIO.output(MotorEnable, GPIO.HIGH)
p_M1.ChangeDutyCycle(level*25)
return level
def main():
lastState=0
level=0
markTemp = temperature()
while True:
currentState =GPIO.input(BtnPin)
currentTemp=temperature()
if currentState == 1 and lastState == 0:
level=(level+1)%5
markTemp = currentTemp
time.sleep(0.5)
lastState=currentState
if level!=0:
if currentTemp-markTemp <= -2:
level = level -1
markTemp=currentTemp
if currentTemp-markTemp >= 2:
level = level +1
markTemp=currentTemp
level = motor(level)
def destroy():
GPIO.output(MotorEnable, GPIO.LOW)
p_M1.stop()
p_M2.stop()
GPIO.cleanup()
if __name__ == '__main__':
setup()
try:
main()
except KeyboardInterrupt:
destroy()
Code Explanation
---------------------
.. code-block:: python
def temperature():
analogVal = ADC0834.getResult()
Vr = 5 * float(analogVal) / 255
Rt = 10000 * Vr / (5 - Vr)
temp = 1/(((math.log(Rt / 10000)) / 3950) + (1 / (273.15+25)))
Cel = temp - 273.15
Fah = Cel * 1.8 + 32
return Cel
``temperture()`` works by converting thermistor values read by **ADC0834**
into temperature values. Refer to :ref:`2.2.2_py` for more details.
.. code-block:: python
def motor(level):
if level == 0:
GPIO.output(MotorEnable, GPIO.LOW)
return 0
if level>=4:
level = 4
GPIO.output(MotorEnable, GPIO.HIGH)
p_M1.ChangeDutyCycle(level*25)
return level
This function controls the rotating speed of the motor. The range of the
**Lever**: **0-4** (level **0** stops the working motor). One level
adjustment stands for a **25%** change of the wind speed.
.. code-block:: python
def main():
lastState=0
level=0
markTemp = temperature()
while True:
currentState =GPIO.input(BtnPin)
currentTemp=temperature()
if currentState == 1 and lastState == 0:
level=(level+1)%5
markTemp = currentTemp
time.sleep(0.5)
lastState=currentState
if level!=0:
if currentTemp-markTemp <= -2:
level = level -1
markTemp=currentTemp
if currentTemp-markTemp >= 2:
level = level +1
markTemp=currentTemp
level = motor(level)
The function **main()** contains the whole program process as shown:
1) Constantly read the button state and the current temperature.
2) Every press makes level\ **+1** and at the same time, the temperature
is updated. The **Level** ranges **1~4**.
3) As the fan works ( the level is **not 0**), the temperature is under
detection. A **2℃\ +** change causes the up and down of the level.
4) The motor changes the rotating speed with the **Level**.
Phenomenon Picture
------------------------
.. image:: ../img/image246.png
:align: center